Fix compiler-generated property backing stores from proxies being introduced erroneously into proxied types.
Fix compiler-generated property backing stores from proxies being introduced erroneously into proxied types.

volkd/JSIL,sander-git/JSIL,TukekeSoft/JSIL,hach-que/JSIL,FUSEEProjectTeam/JSIL,sq/JSIL,sq/JSIL,acourtney2015/JSIL,FUSEEProjectTeam/JSIL,iskiselev/JSIL,dmirmilshteyn/JSIL,sander-git/JSIL,hach-que/JSIL,acourtney2015/JSIL,TukekeSoft/JSIL,x335/JSIL,sq/JSIL,sander-git/JSIL,hach-que/JSIL,iskiselev/JSIL,FUSEEProjectTeam/JSIL,Trattpingvin/JSIL,acourtney2015/JSIL,volkd/JSIL,dmirmilshteyn/JSIL,FUSEEProjectTeam/JSIL,dmirmilshteyn/JSIL,hach-que/JSIL,volkd/JSIL,volkd/JSIL,sander-git/JSIL,iskiselev/JSIL,FUSEEProjectTeam/JSIL,x335/JSIL,iskiselev/JSIL,x335/JSIL,sq/JSIL,mispy/JSIL,Trattpingvin/JSIL,dmirmilshteyn/JSIL,Trattpingvin/JSIL,hach-que/JSIL,antiufo/JSIL,TukekeSoft/JSIL,x335/JSIL,volkd/JSIL,iskiselev/JSIL,acourtney2015/JSIL,mispy/JSIL,antiufo/JSIL,antiufo/JSIL,mispy/JSIL,sander-git/JSIL,Trattpingvin/JSIL,TukekeSoft/JSIL,mispy/JSIL,antiufo/JSIL,acourtney2015/JSIL,sq/JSIL